Patch "xen/gntdev: Fix partial gntdev_mmap() cleanup" has been added to the 4.4-stable tree

This is a note to let you know that I've just added the patch titled

xen/gntdev: Fix partial gntdev_mmap() cleanup

to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
xen-gntdev-fix-partial-gntdev_mmap-cleanup.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Ross Lagerwall <[email protected]>
Date: Tue, 9 Jan 2018 12:10:22 +0000
Subject: xen/gntdev: Fix partial gntdev_mmap() cleanup

From: Ross Lagerwall <[email protected]>

[ Upstream commit cf2acf66ad43abb39735568f55e1f85f9844e990 ]

When cleaning up after a partially successful gntdev_mmap(), unmap the successfully mapped grant pages otherwise Xen will kill the domain if in debug mode (Attempt to implicitly unmap a granted PTE) or Linux will kill the process and emit "BUG: Bad page map in process" if Xen is in release mode.

This is only needed when use_ptemod is true because gntdev_put_map() will unmap grant pages itself when use_ptemod is false.

---
 drivers/xen/gntdev.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

@@ -874,8 +874,10 @@ unlock_out:
 out_unlock_put:
 	mutex_unlock(&priv->lock);
 out_put_map:
-	if (use_ptemod)
+	if (use_ptemod) {
 		map->vma = NULL;
+		unmap_grant_pages(map, 0, map->count);
+	}
 	gntdev_put_map(priv, map);
 	return err;
 }

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/xen-gntdev-fix-off-by-one-error-when-unmapping-with-holes.patch queue-4.4/xen-gntdev-fix-partial-gntdev_mmap-cleanup.patch